With the growing popularity of personal computers, a variety of applications address the needs of the graphics industry. Documents of all kinds are being converted to digital data which is manageable by electronic devices. Graphics has inundated the PC (personal computer) marketplace in the last ten years, due to the implementation of low cost, high-density memories, VLSI graphics controllers, graphics monitors, graphics standards and graphics applications software.
The PC user operates in a monochrome or color graphics platform, depending on the application. Cost used to be significant, and forced the low-end graphics user to select a monochrome system, but recent low-cost color systems have now virtually eliminated this limitation. Within the color marketplace, there are the standard color formats applicable to both the low-end mass marketplace and the high-end specialty marketplace.
The first category typically involves about $500 to $800 for a color graphics card and monitor, and the vast majority of color PC users fall into this category. The second category can involve between $6,000 and $10,000, and only specialty users can justify this cost. Currently, color scanning is available basically for the second of these categories, because it requires high spatial resolution (1024.times. 768) and high-color resolution (24-bit true color) to handle the large data rates. It is a principle goal of the present invention to provide color scanning to the low-end color graphics user.
Relevant popular applications of graphics include illustrations, presentations and publishing. These three applications were each based in large part on the availability of input data and output hard copy technology. The introduction of black and white scanners brought a personal touch to these three applications which was previously impossible. Even more dramatic was the introduction of low-cost laser printers. With these, a user can input data from conventional sources and output it to hard copy, all with an affordable desktop system.
The richness of color was predominantly ignored, due to the unavailability of color images and the expensive printing costs. Now, however, color printers are becoming available at affordable costs, and consequently color scanners are becoming popular. The enormous body of color photographs had remained untouched, due to the costs. This is changing, and those same applications which could afford black and white scanners and laser printers will soon be able to afford color processing. These users will want and need access to color images, and in particular will want to access the images stored on color slides.
Currently, the three graphics applications mentioned above rely on clip art, but current clip art libraries pale in comparison to the images available on 35 mm color slides. An inexpensive slide scanner is essential for users who wish to access these color images. A graphics user can currently get several clip illustrations on a single floppy disk, due to the fact that the binary image format is relatively non-data intensive. A 320 by 200 pixel black and white image can be stored in 8000 bytes. Unfortunately, this is not the case for color images. Currently, a 24-bit color image of the same size would require 192,000 bytes. At current digital storage densities, access speeds and costs, it would not be practical for graphics users to utilize color images in digital formats, especially when one considers that a full page image of 3600 by 2400 pixels requires about 26 megabytes whereas the maximum storage currently available on a standard floppy disk is only 1.44 megabytes.
In order to utilize these color images, it will be necessary to store these color images in their native format, namely on 35 mm color slides. Each slide is small and very inexpensive to reproduce and store. A single standard 120 slide carrousel could store over 3 gigabytes of information. Furthermore, the slides retain their data with minimal care. An inexpensive slide scanner is therefore an absolutely necessary component in the graphics user's computer system.
There are several color scanners currently available on the market which are capable of scanning transparencies, but none of these scanners address the needs of the low-end market. By far the greatest majority of PC users operate with 8-bit color graphics cards and desire a scanner which is simple to use, compact, reliable and inexpensive. A user would not be likely to spend as much money on a slide scanner as was spent on the entire computer system. In addition, it is highly desirable for the scanner to actually mount within the PC, to reduce desktop clutter. Although flexible and powerful, current transparency scanners are expensive, and are designed with a physical size which cannot practically be made sufficiently compact to fit within a conventional PC. Albeit, these allow a wide range of sample size formats (for example from a 35 mm slide transparency to an 8.5 by 11 inch opaque), but at a cost which is unrealistic to the end user. An object of the present invention is to provide a compact and inexpensive system especially designed for a particular size application (for example 35 mm transparencies).
Objects of the present invention include provision of a scanner system which can generate a digital image from a transparency, which is compact, reliable, flexible and inexpensive, and which facilitates computer-based illustration, artwork, presentation graphics, desktop publishing and image database management.
A further object is the provision in the system of capability to directly digitize, store and display images without the need for any intermediate image storage, such as in solid-state or magnetic storage media.
A further object is the provision of capability to display an image with minimal delay, and preferably to effect a full color scan digitizing 480.times.640 pixels in less than ten seconds from the moment a slide starts to move into the system.
It is another object to allow a user to vary the magnification and the location of the image origin (zoom and pan capability), the zoom factor not being limited to integer multiples of the pitch of a solid-state image sensor and the zoom not being implemented in software.
A further object is the provision of a mechanical chassis with the size and shape of a conventional floppy disk drive so that the scanner can be directly installed in a conventional personal computer frame, wherein transparencies or negative strips are inserted into the system through an opening in its front panel, and power requirements of the scanner are met by the internal power (5 Volt, 12 Volt, 20 Watt maximum) supplied in popular computer systems for use by peripherals.
A further object is to provide a system which is self-calibrating, and does not require extensive warmup periods or set-up procedures.
A further object is the provision of a program for the host computer which controls the scanner and allows an operator to interact with the scanning process, and which preferably establishes a windowed environment which allows the operator to open and close files, edit existing images, modify the layout of the window environment, control the color coding, and control the scanner.